Basics of Networking

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					    Basics of Networking



   PRESENTED BY: KEVIN
   SHEA
OTTAWA-CARLETON DISTRICT SCHOOL BOARD
       Kevin_Shea@ocdsb.edu.on.ca


       ACSE CONFERENCE
       FEBRUARY 20, 2004
Basics of Networking


 Networking began its infancy in the mid -1960’s.
 by the US Department of Defence (DoD).

 The original intention of networking was being
 developed to withstand a nuclear war.

 Telephone networks were to vulnerable and would
 terminate all conversations should a nuclear war
 occur.
Basics of Networking




You wake up at 3 a.m. to go to the bathroom and
stop and check your e-mail on the way back to bed.
Basics of Networking



  WE ARE DEALING WITH MACHINES INSTEAD OF
  PEOPLE IN TODAY’S WORLD. OUR PRIVACY IS
  AFFECTED AND ALMOST ALL OF OUR PERSONAL
  INFORMATION CAN BE FOUND IN
  THE “VIRTUAL WORLD” .
Basics of Networking


ARPA (Advanced Research Projects Agency)
was created in response with the launching of the
Sputnik in 1957.
ARPA decided that a DoD network should be packet-
switched networked consisting of a subnet and
host computers.
Experimental network research was awarded to
UCLA, UCSB, SRI and Univ. of Utha in 1969. These
areas were because they all had a large number
of ARPA contracts.
Basics of Networking


These 4 universities also had different and completely
incompatible host computers.

ARPANET protocols were not suitable for running over
multiple networks, so TCP/IP model and protocols
were invented in 1974.

ARPA awarded several other contracts and specifically
Univ.. of California at Berkeley to integrate the
protocols with the Berkeley UNIX.
 Basics of Networking

Berkeley developed a convenient program interface
to the network and wrote many applications, utility,
and management programs to make networking easier.

In it early infancy, the OSI protocols were crushed and
the TCP/IP protocols were already in widespread use.


The OSI Model had seven layers because at the time,
IBM had a propriety seven -layer protocol called
SNA (Systems Network Architecture).
Basics of Networking

At the time, IBM dominated the computer companies
and every was scared to death that IBM would use
its clout to force everyone to use SNA.

The OSI was to be produced like an IBM-reference
model.

The OSI model became the world standard and was
not controlled by one company, but by a neutral
organization, ISO (International Standards Association).
Basics of Networking

TYPES OF NETWORKS
LAN – LOCAL AREA NETWORK IS A SMALL
GEOGRAPHICAL AREA SUCH AS OUR SCHOOL
BOARD.
MAN – METROPOLITAN AREA NETWORK IS A
NETWORK OVER A LARGER GEOGRAPHICAL AREA
SUCH AS THE PROVINCIAL GOVERNMENT.

WAN – WIDE AREA NETWORK IS A NETWORK USED
OVER AN EXTREMELY LARGE GEOGRAPHICAL AREA
SUCH AS THE FEDERAL GOVERNMENT.
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NETWORKS ARE BROKEN INTO 3 TOPOLOGIES.
THEY ARE:


    BUS TOPOLOGY

    STAR TOPOLOGY

    RING TOPOLOGY
Basics of Networking




 BUS TOPOLOGY ALLOWS INFORMATION TO BE
 DIRECTED FROM ONE COMPUTER TO THE OTHER.
 LOTS OF BINARY COLLISION THOUGH.
Basics of Networking




STAR TOPOLOGY IS THE MOST COMMON TYPE
USED. ALL COMPUTERS ARE ATTACHED TO A HUB.
LESS COLLISIONS AND MOST EFFICIENT.
Basics of Networking


RING TOPOLOGY- USES A TOKEN TO PASS
INFORMATION FROM 1 COMPUTER TO THE OTHER.
A TOKEN IS ATTACHED TO THE MESSAGE BY THE
SENDER TO IDENTIFY WHICH COMPUTER SHOULD
RECEIVE THE MESSAGE. AS THE MESSAGE MOVES
AROUND THE RING, EACH COMPUTER EXAMINES
THE TOKEN. IF THE COMPUTER IDENTIFIES THE TOKEN
AS ITS OWN, THEN IT WILL PROCESS THE
INFORMATION.
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 A DISADVANTAGE OF A TOKEN RING IS IF ONE
 COMPUTER IS BROKEN OR DOWN, THE MESSAGE
 CANNOT BE PASSED TO THE OTHER COMPUTERS.
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The seven layers of the OSI Model are:

            Layer   1   PHYSICAL
            Layer   2   DATA- LIN K
            Layer   3   N ETWORK
            Layer   4   TRAN SPORT
            Layer   5   SESSION
            Layer   6   PRESEN TATION
            Layer   7   APPLICATION
Basics of Networking

  •Each one of you was assigned a number when
  you entered the lab. Get together with your team
  member(s).

  •Begin to research the layer that your number is
  associated with.

  •Research as much information as you can in
  15 minutes and make notes of your finding.
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 •Once complete, we will create a bigger group
 with all the layer present.

 •You will present your finding to your group about
 the layer. You will only have 2 minutes to present.
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THE PHYSICAL LAYER
The physical layer is concerned with transmitting
raw bits over a communication channel though
hubs, wires (cat5UTP), modems, network cards…
basically anything that is physical to the network.

In networking, computers are also known as
Hosts or Nodes.

When looking at network cables, there are
2 types that affect nodes. They are:
Basics of Networking


•Straight though cables or also known as patch cables


•Cross-over cables


 The difference in the cables are the way the wires
 are connected within the RJ45. I have attached a
 sheet for you in your package.
Basics of Networking
  Typical Crossover Cable
  Wiring:
  1-3 White/Orange
  2-6 Orange
  3-1 White/Green
  6-2 Green
  4-4 Blue
  5-5 White/Blue
  7-7 White/Brown
  8-8 Brown
Basics of Networking

COMMUNICATION CHANNELS
TWISTED SHIELDED PAIR – USED IN PHONE LINES, NETWORKS

UNSHIELDED TWISTED PAIR “      “      “     “

COAXIAL CABLE – USED IN CABLEVISION GREAT FOR VIDEO

FIBRE OPTIC CABLES - USES LIGHT TO CARRY SIGNAL BUT
HARD TO WORK WITH AND LOOSES SIGNAL OVER LONGER
DISTANCES
Basics of Networking




   Crimping Tool       Hub
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THE DATA-LINK LAYER

The data link layer takes raw transmission and
transform it into a line that appears free of
transmission errors in the network layer.

The Data-Link Layer also is where you would find
the MAC Address. (Media Access Control). To find the
MAC Address of your computer, or any computer:
Start/Programs/MS Prompt and type: ipconfig/all

"C:\WINDOWS>" prompt, type "tracert
www.howstuffworks.com"
Basics of Networking

THE DATA-LINK LAYER

You will also find smart devices such as switches in
the Data-Link Layer.

The digital information that needs to be sent such as
and e-mail, attachments, etc needs to be broken into
smaller bits known as packets.

These packets require some information similar to
sending a letter in the mail.
Basics of Networking


                             Bits of
                          informa tion



  Hea der                                Tra iler (Footer)
  Conta ins :                            Conta ins :
  M a c Address (if a va ila ble)        M a c Address (from your computer)
  IP Address (where it's going)          IP Address (where it ca me from)



  PACKETS


 THERE ARE A NUMBER OF PACKETS THAT WILL
 FOLLOW EACH OTHER TO THE FINAL DESTINATION.
Basics of Networking

THE NETWORK LAYER
The network layer is concerned with controlling
the operation of the subnet. A ROUTER is used to
determining how packets are routed from source
to destination.

If one path is busy, then the router will select another
path for the packets to travel. So really, the packets
can all have different paths and find their way to the
final destination.
Basics of Networking

THE NETWORK LAYER

The router has millions of IP addressing built into
the software, and knows where to send the packets.

IP stands for Internet Protocol and is basically an
address that the packets will be sent to.

An example would be 216.27.61.137
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THE NETWORK LAYER
If you look at the IP Address, the number are broken
into different categories.
                   216. 27.61.137


      Classification                    Hosts

                       216. 27.61.137

                           Octets
Basics of Networking

Classifications can be broken into 3 classes. They are:

Class A - Only the first octet is used for addressing and
          the balance used for hosts.

Class B - The first two octet are used for addressing
         and the balance used for hosts.


Class C - The first three octet are used for addressing
         and the balance used for hosts.
Basics of Networking

Every machine on the Internet has a unique
identifying number, called an IP Address.

 A typical IP address looks like this:
 216.27.61.137


But computers communicate in binary form.
Basics of Networking

The same IP address in binary:


  11011000.00011011.00111101.10001001


                 216.27.61.137
Basics of Networking


If you add all the positions together, you get 32,
which is why IP addresses are considered
32-bit numbers

11011000.00011011.00111101.10001001


Combine the four octets and you get 232 or a possible
4,294,967,296 unique values.
Basics of Networking

Class A - This class is for very large networks,
such as a major international company might have.
IP addresses with a first octet from 1 to 126 are
part of this class.
Basics of Networking


Class B - This class is used for medium-sized networks.
A good example is a large college campus.
IP addresses with a first octet from 128 to 191
are part of this class. Class B addresses also include
the second octet as part of the Net identifier.
Basics of Networking


Class C - Class C addresses are commonly used for
small to mid-size businesses. IP addresses
with a first octet from 192 to 223 are part of this
class. Class C addresses also include the second
and third octets as part of the Net identifier.
Basics of Networking

 LOOPBACK
 Loopback - The IP address 127.0.0.1 is used
 as the loopback address. This means that it is
 used by the host computer to send a message
 back to itself.
Basics of Networking

THE TRANSPORT LAYER

The transport layer “DIRECTS PACKETS”, splits it up into
smaller units if need be, pass these to the network
and ensure that the pieces are travelling in an
orderly fashion.

A series of protocols are also established in this
layer to ensure proper flow of the packets.

You can basically describe the Transport Layer as
a “TRAFFIC COP”.
Basics of Networking

THE SESSION LAYER

The session layer allows different machines to
establish sessions between themselves.

Once communications are established, encryption
then begins both parties.
Basics of Networking

THE PRESENTATION LAYER
The Presentation Layer’s job is managing data
structures and converting from the representation
used inside the computer to the network standard
representation an visa versa.
In English terms, the Presentation layer basically
takes the packets and re-assembles them so you can
open the e-mail or the attachment.
If any packets got lost along the way, or were
damaged, then the Presentation layer will send a
sign to the sender that it requires the specific packet.
Basics of Networking

THE APPLICATION LAYER
The Application layer contains a variety of protocols
that are commonly required.

Another Application layer function is file transfer.

Different file systems have different file naming
conventions, different ways of representing text lines,
and so on.
Transferring a file between two different systems
requires handling and other incompatibilities.
Basics of Networking

THE APPLICATION LAYER
 FTP - File Tra nsfer Protocol
 FTP provides a sta ndard system for sending
 a nd receiving files over IP networks.

 HTTP Protocol
 Web browsers a nd servers use the Hypertext
 Tra nsfer Protocol (HTTP) protocol to
 communica te.

 Electronic Mail Protocols
 Severa l network protocols were developed
 specifica lly to support electronic ma il over the
 Internet.
Basics of Networking

THE APPLICATION LAYER
 SOAP - Simple Object Access
 Protocol
 SOAP defines a sta nda rd wa y to encode objects
 within network pa ckets using XML.

 DHCP
 The Dyna mic Host Configura tion Protocol
 (DHCP) supports a utoma tic a ddress a ssignment
 a nd improved configura tion ma nagement of IP
 networks.
Basics of Networking

THE APPLICATION LAYER

  IPv6 - Internet Protocol version 6
  IPv6 promises to relieve the current IP a ddress
  shorta ge, a nd this new version of the protocol
  ma y a lso increa se performa nce a nd improve
  a dministra tion ca pabilities.

  PPPoE
  The Point to Point Protocol over Ethernet
  (PPPoE) sta ndard helps a ccess providers
  ma na ge their broadba nd service delivery, a nd
  it ca n a lso improve the ea se of use for DSL a nd
  ca ble modem customers.
Basics of Networking

As you can see, the OSI Model is a sophisticated
and complicated model, but I hope you gained
some information on the way this theoretical model
work.


The package that I have given you also has an
IP Addressing assignment that I use with my Grade
12 Computer Engineering Students.
Basics of Networking




           Thank You.
Basics of Networking

RESOURCES
http:/ / www2.rad.com/ networks/ 1994/ osi/ osi.htm

http://compnetworking.about.com/library/glossary/bldef-bandwidth.htm

http:/ / www.dei.isep.ipp.pt/ docs/ arpa- - 1.html

www.3com.com/other/pdfs/infra/ corpinfo/en_US/501302.pdf - IP Addressing

http://computer.howstuffworks.com/question549.htm

Networks, Interfaces and Integrated Circuits
( Graham Smyth and Christine Stephenson)

www.cisco.com

				
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